-LRB- CNN -RRB- -- Professor Peter Furth has ridden his bicycle to work at Northeastern University each day for the past six years . The two-mile trip through the Boston suburb of Brookline , Massachusetts , is usually without incident .

Furth 's journey is worlds apart from his former Boston commute , which for 13 years was a battle with drivers who wanted him on the sidewalk .

`` I 've had motorists that drive a couple of inches from my elbow , trying to scare me , '' he said .

Furth would catch up with drivers at stoplights and ask them whether they knew how close they 'd come to hitting him . Invariably , they would say , `` Yes , move over . ''

It 's a cultural thing , he said .

In the town of Cambridge , motorists see bicyclists all over the place and are considerate . In Brookline , only every now and then does someone honk or yell .

In the southern part of Boston , it 's not quite war , but the relationship is n't very friendly .

Although the street signs say `` Share the road , '' there 's still a long road to travel before that sign reflects the reality , bicyclists say .

Motorists often see bands of bikes on the streets on the final Fridays of each month as cyclists across the nation gather for evening group rides called Critical Mass. .

The purpose , advocates say , is to make cars and trucks more aware of bicyclists .

But to some drivers , Critical Mass participants are nothing more than spandex-wearing , stop-sign-running Lance Armstrong wannabes who slow traffic .

` They think they own the road '

It 's somewhat symbolic of the tension on the roads .

`` The roads were made for cars , '' KTAR-FM radio guest host John Hook said in Phoenix , Arizona , last month . `` And bicyclists share the road , but sometimes they think they own the road . ''

One caller to the program was a long-haul truck driver who accused many bicycle riders of failing to respect the law and not riding with the flow of traffic .

A caller who identified himself as Jeff said he witnessed an incident in which a pack of bicyclists almost hit a car that had the right of way . Then the riders screamed at the motorist .

`` I actually think the bikes are more disrespectful to the cars than the cars are to the bike , '' Jeff said .

The number of cyclists is increasing .

Although bike sales took a dip during the recession of 2009 , more than 18 million were sold each year for the seven previous years , according to the National Sporting Goods Association .

About 27 percent of adults in the United States bike at least once a summer , according a survey released in 2008 by the National Highway Traffic Safety Administration .

Most bicyclists ride for recreation or exercise , while a small percentage ride to work . In Portland , Oregon , which is ranked second on Bicycling magazine 's list of Top 50 Bike Friendly Cities , more than 6 percent of residents commute by bike to work . That 's up from 1 percent two decades ago .

See a map of the top 10 bike-friendly cities

Things are looking up , at least in the eyes of cyclists . Many cities are putting in bike lanes and paths .

Google adds bike routes to maps

More than $ 730 million in federal stimulus funds has been allocated for bike and pedestrian projects , according to AmericaBikes.org .

Washington is getting into the act . U.S. Secretary of Transportation Ray LaHood drew cheers from the cycling world in March when he blogged that the administration was `` integrating the needs of bicyclists in federally-funded road projects '' and advising state departments of transportation to treat biking and walking `` as equals with other transportation modes . ''

That drew an outcry from industry , which saw the new policy as taking money away from large transportation construction needs .

`` Treating bicycles and other non-motorized transportation as equal to motorized transportation would cause an economic catastrophe , '' Carter Wood , a senior adviser at the National Association of Manufacturers , told The New York Times . `` If put it into effect , the policy would more than undermine any effort the Obama administration has made toward jobs . You ca n't have jobs without the efficient movement of freight . ''

Five blocks of controversy

Michael Ritchey is an avid biker and believes that bike lanes are good idea . He just thinks the project to add them to a five-block stretch of Hillsborough Street in Raleigh , North Carolina , is folly -- and dangerous .

Hillsborough Street is one of the main arteries in Raleigh and borders the northern part of North Carolina State University and its 30,000 students . There are bars and shops and small restaurants . And lots of cars .

The city , working with the state , has decided to redo the four-lane road , and when the project is done , there will be two lanes for cars , a center median and bike lanes on each side . Ritchey , who owns Global Village Organic Coffee and is a weekend cyclist , fears that bikers will get hurt .

`` They are putting -LSB- the bike lanes -RSB- in the wrong place , '' he said . `` It 's more of a symbolic gesture . ''

And it does n't help that the relationship between cars and bicyclists in the city is `` antagonistic at best , '' he said .

Ritchey is worried that distracted college students wo n't be on the lookout for bikers and someone will get hurt when a car door opens at the wrong time or someone texting will have an accident -LRB- he 's seen that twice with cars -RRB- . He said one of his business neighbors opposes the projects because he fears that he will lose parking spaces in front of the bar .

City councilwoman Nancy McFarlane points out that the bikers are already there on Hillsborough and other in-town streets , and the city of 348,000 is growing quickly . Many people are moving into the downtown area , and last year , the city revised its comprehensive plan .

`` The old one was all about the car , and we want to become a multimodal city , '' she said . `` That includes bikes , buses and light rail . ''

Steve Waters is one resident in favor of bike lanes . The freelance programmer works at home and uses his bike for short errands . He said that although some Hillsborough Street business owners might be concerned about losing money because of less car traffic , the opposite is likely to happen .

`` It enhances the local economy , '' he said . `` It 's all about creating options . ''

Bicycling.com : The best road bikes of 2010

Not every street should get a bike lane

Although opponents say the money is better spent on other road projects , cycling advocates say the lanes are needed to make the roads safer and less congested .

Denver , Colorado , is ranked 12th on Bicycling magazine 's list . The city has little room for new roads , municipal bike planner Emily Kreisa said . She said Denver is interested in using bicycles to eliminate congestion and to help the environment , but they do n't just add a bike lane anywhere .

Bicycling.com : Five cities to watch

`` We look at the traffic volume , the turning issues and how much room we have in the right of way , '' she said . `` In choosing any kind of -LSB- project -RSB- , the first thing is what is the connection to the system , then what is the characteristic of the road and then how do we need to provide for the cyclist . ''

Denver received $ 250,000 of stimulus money for cycling projects and is going to add 11 miles of bike lanes . The city is using its own funds to paint sharrows -LRB- painted bike symbols on the asphalt with arrows showing cyclists the way -RRB- to connect the roads of the network .

Kreisa , who bikes 10 miles to work , says Denver is by far the easiest place she has commuted on two wheels .

`` I 've had one person honk at me and one person tell me to move over to the right , '' she said of her two years in the city . `` There are a lot of active people here who are also cyclists . ''

@highlight

Number of U.S. bicyclists is increasing , according to government study

@highlight

More than $ 700 million in stimulus funds is being used for bike and pedestrian projects

@highlight

Critics question project in North Carolina that would add bike lanes to busy street

@highlight

Cities should choose wisely where to add lanes , paths , expert says